The industry watchdog said: "Re-touching images is acceptable so long as the resulting effect was not one which misleadingly exaggerated the effect that the product was capable of achieving.

"Although we considered that the image in the ad did not misrepresent the luminosity or wrinkling of Rachel Weisz's face, we considered that the image had been altered in a way that substantially changed her complexion to make it appear smoother and more even.

"We therefore concluded that the image in the ad misleadingly exaggerated the performance of the product in relation to the claims 'skin looks smoother' and 'complexion looks more even.'"

They said it breached industry rules relating to misleading advertising and exaggeration.

L'Oreal said it had sought to represent the actress as favourably as possible.

Six readers complained about the photo of Jane Fonda in the same firm's advert for Age Re-Perfect moisturiser.

They said it misleadingly exaggerated the effect that could be achieved.

But the ASA said: "The overall appearance of the image of Jane Fonda that appeared in the ad had not been significantly modified.

"We therefore concluded that the image in the ad did not exaggerate the effect that could be achieved by the product and that the ad was not misleading."